One of the critical problems in the design of Wankel-type rotary piston mechanisms is to provide an efficient sealing grid system whereby the working chambers are substantially completely isolated from each other. The most successful sealing grid systems, to date, have been those employing apex seal pins sealingly interconnecting the apex seal blade with the ends of side gas seal strips as exemplified in the Wankel et al U.S. Pat. No. 3,064,880 dated Nov. 20, 1962 and the U.S. Pat. to Fisch, Nos. 3,134, 600 dated May 26, 1964; Bentele, 3,180,562 dated Apr. 27, 1965; Jones, 3,400,691 dated Sept. 10, 1968; and Larrinaga et al, 3,674.384 dated July 4, 1972. While these sealing grid systems are practical and effective, they are relatively expensive and in small engine applications, as for example, lawnmowers, chainsaws and the like, may reduce the competitive advantages over conventional small reciprocating piston engines. One reason for the costliness of such sealing grid systems is the expense of accurately machining the seal pin holes, the slots in the seal pins to match the slots in the rotor apex, and the steps in the pins so as to properly receive, in abutment, the gas seal strips. Also, such a relatively complex sealing grid system represents costly assembly procedures. Obviously, a simplified sealing grid system, which eliminates the necessity for apex seal pins, would materially reduce the cost of an engine and render it more competitive with the conventional reciprocating piston engines.
Accordingly, it is an object of this invention to provide a sealing grid system for a Wankel-type engine which is relatively simple, inexpensive and obviates the necessity for apex seal pins.
It is another object of the present invention to provide a sealing grid system for a Wankel-type engine which is sufficiently effective to be suitable for small sized engines where efficiency is of secondary concern.